Flexible dynamic riser for subsea well intervention

ABSTRACT

A flexible dynamic riser comprising: a riser; a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus; and a packing material disposed within the annulus.

CROSS REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of U.S. Provisional Application No. 62/200,922, filed Aug. 4, 2015, which is incorporated herein by reference.

BACKGROUND

The present disclosure relates generally to flexible dynamic risers. More specifically, in certain embodiments the present disclosure relates to flexible dynamic risers useful for performing for well interventions and associated methods and systems.

In the oil and gas industries, coiled tubing is often used for interventions in oil and gas wells and sometimes as production tubing in depleted gas wells. Coiled tubing may be used to perform in well interventions such as clean outs, chemical stimulations, drilling, milling, and diagnostic operations. Coiled tubing may also be used to fracture reservoirs.

In order to perform an operation with coiled tubing, the coil tubing must first be deployed. The first step of deploying coiled tubing typically involves deploying and interfacing a lower marine riser package (LMRP) with an emergency disconnect package (EDP) to a subsea tree. The next step typically involves running a top tension marine riser through the water column. The top tension marine riser may be run in separate straight sections, wherein each section may be approximately 90 feet to 120 feet in length. The riser may then be secured to the LMRP and/or EDP and then a lift frame with a blow out preventer (BOP) and injector head may be suspended by draw works. This assembly may then be then attached to the riser. The riser may then be displaced to a wellbore compatible brine of specific density as to provide well control barrier. The coiled tubing along with a bottom hole assembly (BHA) may then be routed from a reel through the injector head and BOP.

Such current methods and systems typically require the use of a mobile offshore drilling unit (MODU) or an intervention rig in order to be deployed. The costs to deploy a MODU or an intervention rig can exceed 1,000,000/day. Additionally, the availably of a MODU or an intervention rig may be an issue.

It is desirable to develop a system useful for performing coil tubing interventions that may be deployed without the use of a MODU or an intervention rig.

SUMMARY

The present disclosure relates generally to flexible dynamic risers. More specifically, in certain embodiments the present disclosure relates to flexible dynamic risers useful for performing for well interventions and associated methods and systems.

In one embodiment, the present disclosure provides a flexible dynamic riser comprising: a riser; a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus; and a packing material disposed within the annulus.

In another embodiment, the present disclosure provides a riser system comprising: a flexible dynamic riser, wherein the flexible dynamic riser comprises a riser; a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus; and a packing material disposed within the annulus; a vessel; and a wellhead, wherein the flexible dynamic riser is connected to the vessel and the wellhead.

In another embodiment, the present disclosure provides a method comprising: providing a flexible dynamic riser, wherein the flexible dynamic riser comprises a riser, a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus, and a packing material disposed within the annulus and deploying the flexible dynamic riser.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings.

FIG. 1 illustrates a cross section of a portion of a flexible dynamic riser in accordance wither certain embodiments of the present disclosure.

FIG. 2 illustrates a riser system in accordance with certain embodiments of the present disclosure.

The features and advantages of the present disclosure will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the disclosure.

DETAILED DESCRIPTION

The description that follows includes exemplary apparatuses, methods, techniques, and/or instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

The present disclosure relates generally to flexible dynamic risers. More specifically, in certain embodiments the present disclosure relates to flexible dynamic risers useful for performing for well interventions and associated methods and systems.

One potential advantage of the flexible dynamics risers discussed herein is that their use may reduce the costs of interventions. Another potential advantage of the flexible dynamic risers discussed herein is that they are more versatile than conventional top tension riser systems, thus able to be deployed from a multi service vessel rather than requiring the use of a MODU or an intervention rig.

In certain embodiments, the present disclosure provides a flexible dynamic riser. Referring now to FIG. 1, FIG. 1 illustrates a cross section of a portion of flexible dynamic riser 100. In certain embodiments, flexible dynamic riser 100 may comprise riser 110, liner 120, and coil tubing 130.

In certain embodiments, riser 110 may comprise a flexible composite pipe or tube. In certain embodiments, riser 110 may comprise a reinforced composite riser. In certain embodiments, the length of riser 110 may vary depending on the water depth. In certain embodiments, riser 110 may have a length that is in the range of from 100 feet greater than the depth of the water to 1000 feet greater than the depth of the water. In certain embodiments, riser 110 may have a length that is in the range of from 200 feet greater than the depth of the water to 500 feet greater than the depth of the water. In certain embodiments, riser 110 may have a length that is in the range of from 500 feet to 20,000 feet.

In certain embodiments, riser 110 may have an inner diameter that is in the range from 0.5 inches to 6.5 inches. In certain embodiments, riser 110 may have an inner diameter that is in the range of from 2 inches to 4 inches. In certain embodiments, riser 110 may have an inner diameter that is in the range of from 2.25 inches to 2.5 inches. In certain embodiments, riser 110 may have an outer diameter that is in the range of from 2 inches to 6 inches. In certain embodiments, riser 110 may have an outer diameter that is in the range of from 2.5 inches to 5 inches. In certain embodiments, riser 110 may have an outer diameter that is in the range of from 2.75 inches to 3.5 inches.

In certain embodiments, liner 120 may be disposed within riser 110. In certain embodiments, liner 120 may comprise a molded in wear liner. In certain embodiments, liner 120 may be a composite liner or comprise an ultra-high molecular weight plastic. In certain embodiments, the ultra-high molecular weight plastic may exhibit low wear and high lubricity characteristics.

In certain embodiments, coil tubing 130 may be disposed within liner 120 and/or riser 110. In certain embodiments, coil tubing 130 may comprise any conventional type of coil tubing. In certain embodiments, coil tubing 130 may have an outer diameter of 2 inches. In certain embodiments, coil tubing 130 may have an outer diameter greater than 2 inches. In certain embodiments, coil tubing 130 may be capable of performing any type of well intervention typically performed by coil tubing. In certain embodiments, coil tubing 130 may be configured to be attached to a bottom hole assembly.

In certain embodiments, coil tubing 130 and liner 120 (or alternatively riser 110) may define an annulus 140. In certain embodiments, annulus 140 may have an outer diameter equal to the inner diameter of liner 120 or riser 110. In certain embodiments, annulus 140 may have an inner diameter equal to the outer diameter of coil tubing 130. In certain embodiments, annulus 140 may have an inner radius and an outer radius. In certain embodiments, the difference between the outer radius of annulus 140 and inner radius of 140 may be a value in the range of from 0.1 inches to 0.5 inches. In other embodiments, the difference between the outer radius of annulus 140 and inner radius of 140 may be in a value in the range of from 0.025 inches to 0.1 inches. In other embodiments, the difference between the outer radius of annulus 140 and inner radius of 140 may be a value in the range of from 0.0125 inches to 0.025 inches.

Additionally, in alternative embodiments not illustrated in FIG. 1, an electrical umbilical and/or a wireline may be disposed within liner 120 and/or riser 110 along with, or instead of, coil tubing 130. In certain embodiments, the wireline may be capable of performing wireline interventions. Examples of wireline interventions that the wireline may be capable of performing include milling, sleeve shifts, bailing, sampling, installing or removing packers and plugs, inspections and loggings.

In certain embodiments, annulus 140 may be filled with a packing material 145. In certain embodiments, material 145 may be a viscous fluid. Examples of suitable viscous fluids include synthetic based fluids, oil based fluids, and water based fluids. In certain embodiments, material 145 may comprise honey oil. In other embodiments, the material 145 may be grease. In other embodiments, the material 145 may be a lubricant.

In certain embodiments, the material 145 within annulus 140 may prevent annulus 140 from closing as flexible dynamic riser 100 is used thus preventing a kink in flexible dynamic riser 100 from forming. In certain embodiments, material 145 may serve as a pressure barrier preventing the flow of fluids up through annulus 140. In certain embodiments, material 145 may serve as a barrier preventing any flow or pressure from the well to reach the surface. In certain embodiments, material 145 may also serve as a lubricant to reduce friction between riser 110 and/or liner 120 and coiling tubing 130. In certain embodiments, material 145 may be pressurized from grease pumps on the surface to provide sufficient pressure to balance any wellbore or pipeline pressure. In certain embodiments, the grease pumps may also provide make up material for any lost material in the annulus.

In certain embodiments, not illustrated in FIG. 1, flexible dynamic riser 100 may further comprise one or more buoyancy modules. In certain embodiments, the buoyancy modules may comprise any conventional buoyancy modules. In certain embodiments, the buoyancy modules may comprise a composite a synthetic foam material. In other embodiments, the buoyancy modules may comprise a composite material constructed of small glass spheres in a hardened resin. In certain embodiments, the buoyancy modules may be clamped around riser 110. In other embodiments, the buoyancy modules may be suspended from riser 110.

In certain embodiments, the buoyancy modules may be attached to riser 110 at lengths starting from 100 feet from the surface. In certain embodiments, the buoyancy modules may be attached to riser 110 at length of 250 feet from the end of riser 110. In certain embodiments, no buoyancy modules may be attached to the riser at positions less than 250 feet from the end of riser 110 or 500 feet from the surface. In certain embodiments, the one or more buoyancy modules may be attached to riser 110 in a configuration that enables flexible dynamic riser 100 to form one or more coils.

In certain embodiments, not illustrated in FIG. 1, riser 110 may further comprise one or more packing glands. In certain embodiments, the packing glands may comprise any conventional packing gland. In certain embodiments, the one or more packing glands may be installed on each end of the riser. In certain embodiments, the one or more packing glands may prevent the flow of the material out either end of the riser.

Referring now to FIG. 2, FIG. 2 illustrates a riser system 1000. In certain embodiments, riser system 1000 may comprise flexible dynamic riser 1100, vessel 1200, and wellhead 1300.

In certain embodiments, flexible dynamic riser 1100 may comprise any combination of features discussed above with respect to flexible dynamic riser 100. In certain embodiments, flexible dynamic riser 1100 may be capable of being deployed from vessel 1200. In certain embodiments, flexible dynamic riser 1100 may be capable of performing an intervention operation on wellhead 1300.

In certain embodiments, flexible dynamic riser 1100 may be deployed in a “coil configuration.” As used herein, the term “coil configuration” describes a deployment flexible dynamic riser 1100 in a manner such that one or more coil portions 1101 are formed. In certain embodiments, flexible dynamic riser 1100 may comprise one, two, three, four, five, or more coil portions 1101. In certain embodiments, each coil may comprise between 50-200 feet of coil tubing. In certain embodiments, coil portions 1101 may comprise one or more buoyancy modules 1102. In certain embodiments, buoyancy modules 1102 may comprise any combination of features of the buoyancy modules discussed above.

In certain embodiments, each of the one or more coil portions 1101 may be at least 250 feet from well head 1300. In certain embodiments, each of the one or more coil portions 1101 may be at least 500 feet from the vessel 1200. In other embodiments, one or more of the one or more coil portions 1101 may be a distance in the range of from 100 feet to 500 feet from the vessel 1200.

In certain embodiments, the coil configuration of flexible dynamic riser 1100 may be formed at least in part by the placement of buoyancy modules 1102. In certain embodiments, the coil configuration of flexible dynamic riser 1100 may be formed at least in part during fabrication of the flexible dynamic riser 1100. For example, in certain embodiments, the one or more coil portions 1101 may be formed in coil configurations and then be connected to segments of the flexible dynamic riser 1100 when it is being deployed through the use of connectors.

In certain embodiments, the coil configuration of flexible dynamic riser 1100 may absorb vessel movement thus eliminating the need for tensioners or towers. In certain embodiments, flexible dynamic riser 1100 may be fluidly connected to a stuffing box (not illustrated in FIG. 2) on vessel 1200.

In certain embodiments, flexible dynamic riser 1100 may further comprise a bottom-hole assembly 1104. In certain embodiments, bottom-hole assembly 1104 may comprise an injector, a jetting nozzle, a drill motor, a drill bit, a diagnostic logging tool, a fishing tool, a packer, or a milling tool.

In certain embodiments flexible dynamic riser 1100 may be connected well head 1300. In certain embodiments, well head 1300 may comprise an emergency disconnect package 1301. In certain embodiments, the emergency disconnect package 1301 may provide the interface between wellhead 1300 and flexible dynamic riser 1100. In certain embodiments, emergency disconnect package 1301 may be comprise a port 1302 that allows return fluid and/or cuttings to be diverted through return tubing 1400 to vessel 1200.

In certain embodiments, emergency disconnect package 1301 may comprise a lubricator, an injection head, and a shear and pressure containment system. In certain embodiments, the shear and pressure containment system may be capable of shearing the coil tubing, providing dual barrier protection, and releasing FDR and other attached tubing or umbilical during an emergency.

In certain embodiments, flexible dynamic riser 1100 may further comprise a bend limiter 1105 and/or a bend restrictor 1106. In certain embodiments, bend limiter 1105 may be installed onto flexible dynamic riser 1100 at wellhead 1300. In certain embodiments, bend restrictor 1106 may be installed onto flexible dynamic riser 1100 at vessel 1200. In certain embodiments, the bend limiter 1105 and/or bend restrictor 1106 may prevent flexible dynamic riser 1100 from clashing as the vessel 1200 moves relative to wellhead 1300.

In certain embodiments, vessel 1200 may be a multi service vessel or a vessel purpose built for this operation. In certain embodiments, vessel 1200 may comprise reel 1201 and sheave 1202.

In certain embodiments, reel 1201 may be capable of deploying flexible dynamic riser 1110 and recovering flexible dynamic riser 1110. In certain embodiments, reel 1201 may provide the required force/torque to deploy and recover flexible riser dynamic riser 1110. In certain embodiments, reel 1201 may be able to store flexible dynamic riser 1110 when it is not being used. In certain embodiments, sheave 1202 may be capable of directing and guiding flexible dynamic riser 1110 from reel 1201 to a vertical position into the water column.

In certain embodiments, the riser system 1000 may further comprise an ROV 1500. In certain embodiments, ROV 1500 may be capable of attaching flexible dynamic riser 1110 to well head 1300.

In certain embodiments, the present disclosure provides a method comprising: providing a riser system comprising a flexible dynamic riser and a subsea well and deploying the flexible dynamic riser. In certain embodiments, the riser system may comprise any combination of features discussed above with respect to flexible dynamic riser system 1000. In certain embodiments, the flexible dynamic riser may comprise any combination of features discussed above with respect to flexible dynamic riser 100 and/or flexible dynamic riser 1100. In certain embodiments, the subsea well head may comprise any combination of features discussed above with respect to well head 1300.

In certain embodiments, providing a flexible dynamic riser may comprise providing a vessel comprising a reel and a sheave, wherein the flexible dynamic riser is disposed on the reel. In certain embodiments, the vessel may comprise any combination of features discussed above with respect to vessel 1200.

In certain embodiments, deploying the flexible dynamic riser may comprise deploying the flexible dynamic riser from the vessel. In certain embodiments, deploying the flexible dynamic riser may first comprise attaching an end of the coiled tubing of the flexible dynamic riser to a bottom hole assembly.

In certain embodiments, deploying the flexible dynamic riser may comprise: deploying a first length of the flexible dynamic riser from the vessel. In certain embodiments, the first length of the flexible dynamic riser may comprise 250 feet. In certain embodiments, the first length of the flexible dynamic riser may or may not have any buoyancy modules attached to the flexible dynamic riser.

In certain embodiments, deploying the flexible dynamic riser may further comprise deploying a second length of the flexible dynamic riser from the vessel. In certain embodiments, the second length of the flexible dynamic riser may depend on the depth of the water, the length of the first length of the flexible dynamic riser, and the number of coils. In certain embodiments, the length of the second length of the flexible dynamic riser may be greater than the depth minus 750 feet.

In certain embodiments, deploying the second length of the flexible dynamic riser may comprise attaching one or more buoyancy modules to the second length of the flexible dynamic riser. In certain embodiments, the buoyancy modules may be attached to the flexible dynamic riser using a mechanical clamp or a flexible strap. In certain embodiments, the second length of flexible dynamic riser may have a coil configuration that was formed during the fabrication of the second length of flexible dynamic riser flexible dynamic riser. In such embodiments, the second length of flexible dynamic riser may be connected to the first length of flexible dynamic riser before it is deployed.

In certain embodiments, deploying the flexible dynamic riser may comprise deploying a third length of the flexible dynamic riser. In certain embodiments, the third length of the flexible dynamic riser may comprise 500 feet. In certain embodiments, the third length of the flexible dynamic riser may or may not have any buoyancy modules attached to the flexible dynamic riser.

In certain embodiments, deploying the first length, second length, and deploying the third length may allow for the flexible dynamic riser to be deployed in a coiled configuration. In certain embodiments, deploying the flexible dynamic riser may comprise deploying the flexible dynamic riser in a coil configuration.

In certain embodiments, deploying the flexible dynamic riser may further comprise attaching the flexible dynamic riser to the subsea wellhead. In certain embodiments, the flexible dynamic riser may be connected to an EDP on the subsea well head. In certain embodiments, an ROV may attach the flexible dynamic riser to the EDP.

In certain embodiments, the flexible dynamic riser may be attached to the EDP after the entire third length of flexible dynamic riser has been deployed. In other embodiments, the flexible dynamic riser may be attached to the EDP while the third length of flexible dynamic is being deployed.

In certain embodiments, the method may further comprise connecting the flexible dynamic riser to a connector located on a deck of the vessel.

In certain embodiments, the method may further comprise attaching a return tubing to a port on the EDP. In certain embodiments, an ROV may be used to attach the return tubing to the port on the EDP.

In certain embodiments, method further comprises performing a subsea well intervention with the coil tubing.

While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions and improvements are possible.

Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter. 

1. A flexible dynamic riser comprising: a riser; a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus; and a packing material disposed within the annulus.
 2. The flexible dynamic riser of claim 1, wherein the riser comprises a reinforced composite riser.
 3. The flexible dynamic riser of claim 1, wherein the riser has an inner diameter in the range of from 0.5 inches to 6.5 inches.
 4. The flexible dynamic riser of claim 1, wherein the riser comprises a liner.
 5. The flexible dynamic riser of claim 1, wherein the packing material is a viscous fluid.
 6. The flexible dynamic riser of claim 1, wherein the packing material is grease.
 7. The flexible dynamic riser of claim 1, wherein the flexible dynamic riser further comprises one or more buoyancy modules.
 8. The flexible dynamic riser of claim 7, wherein the buoyancy modules are attached to the riser in a configuration that enables the flexible dynamic riser to form one or more coils.
 9. The flexible dynamic riser of claim 1, wherein the flexible dynamic riser further comprises one or more packing glands.
 10. A riser system comprising: a flexible dynamic riser, wherein the flexible dynamic riser comprises a riser, a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus, and a packing material disposed within the annulus.
 11. The riser system of claim 10, wherein the flexible dynamic rise comprises the flexible dynamic riser.
 12. The riser system of claim 10 or 11, further comprising a vessel and a wellhead, wherein the flexible dynamic riser is connected to the vessel and the wellhead.
 13. The riser system of claim 10, wherein the flexible dynamic riser is deployed in a coil configuration.
 14. The riser system of claim 10, wherein the flexible dynamic riser comprises three coil portions.
 15. The riser system of claim 10, wherein the flexible dynamic riser further comprises a bottom-hole assembly.
 16. A method comprising: providing a flexible dynamic riser, wherein the flexible dynamic riser comprises a riser, a coil tubing disposed within the riser, wherein the riser and the coil tubing define an annulus, and a packing material disposed within the annulus and deploying the flexible dynamic riser.
 17. The method of claim 16, wherein the flexible dynamic risers comprises the flexible dynamic riser
 18. The method of claim 16, wherein deploying the flexible dynamic riser comprises attaching the flexible dynamic riser to a subsea well head.
 19. The method of claim 16, wherein deploying the flexible dynamic riser comprises deploying the flexible dynamic riser in a coil configuration.
 20. The method of claim 16, further comprising performing a subsea well intervention with the coil tubing. 